The present invention relates generally to fiber optic devices, and particularly, to fiber optic lasers.
A few demonstrations of low threshold laser optical sources using ring fiber resonators have been reported, including: L. F. Stokes, et al., "All-Fiber Stimulated Brillouin Ring Laser With Submilliwatt Pump Threshold," Optics Letters, Vol. 7, No. 10, p. 509 (1982); E. Desurvire, et al., "Theory and Implementation of a Raman Active Fiber Delay Line," IEEE Journal of Lightwave Technology (April, 1986); and W. V. Sorin, et al., "Single Mode Fiber Ring Dye Laser," Optics Letters, Vol. 10, No. 11, p. 550 (1985). These low threshold laser optical sources were realized in all single-mode fiber versions by means of evanescent-field fiber couplers, such as those described by M. Digonnet, et al., in an article entitled "Analysis of a Tunable Single Mode Optical Fiber Coupler," IEEE Journal of Quantum Electronics, Vol. QE-18, No. 4, p. 746 (1982). Synchronously pumped fiber oscillators based on stimulated Raman scattering (SRS) have also been achieved in bulk optics. For example, such oscillators are described in the following articles: Chinlon Lin, et al., "A Tunable 1.1 .mu.m Fiber Raman Oscillator," applied Physics Letters, Vol. 31, No. 2, p. 97 (1977); R. H. Stolen, et al., "A Fiber Raman Ring Laser," IEEE Journal of Quantum Electronics, Vol. QE-14, No. 11, p. 860 (1978); and A. R. Chraplyvy, et al., "Synchronously Pumped D2 Gas-In Glass Fiber Raman Case Operating at 1.56 .mu.m," Optics Letters, Vol. 9, No. 6, p. 241 (1984).